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Re: Using libcurl/SSL with in-core certificate - solved

From: theo borm <theo_curl_at_borm.org>
Date: Wed, 24 Aug 2005 17:37:28 +0200

Dear list members,

To give a definitive answer to my own question and hopefully
help others who (in the future) may have similar problems, a
small piece of code with a self-contained example, is attached
below.

As usual, looking in the wrong direction makes things appear
harder than they really are.

thanks.

cheers, Theo

<----- cut here ----->

/* example using a "in core" PEM certificate to retrieve a https page */

/* on a netBSD system with OPENSSL& LIBCURL installed from
 * pkgsrc (using default paths) this program can be compiled using:
 * gcc -I/usr/pkg/include -L/usr/pkg/lib -lcurl -Wl,-R/usr/pkg/lib -lssl
-lcrypto -lz -o curlcacerttest curlcacerttest.c
 * on other operating systems you may want to change paths to headers
 * and libraries
 */
#include <openssl/ssl.h>
#include <curl/curl.h>
#include <stdio.h>

size_t writefunction( void *ptr, size_t size, size_t nmemb, void *stream)
{
    fwrite(ptr,size,nmemb,stream);
    return(nmemb*size);
}

static CURLcode sslctx_function(CURL * curl, void * sslctx, void * parm)
{
    X509_STORE * store;
    X509 * cert=NULL;
    BIO * bio;
    char * mypem = /* www.cacert.org */
        "-----BEGIN CERTIFICATE-----\n"\
        
"MIIHPTCCBSWgAwIBAgIBADANBgkqhkiG9w0BAQQFADB5MRAwDgYDVQQKEwdSb290\n"\
        
"IENBMR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNB\n"\
        
"IENlcnQgU2lnbmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRA\n"\
        
"Y2FjZXJ0Lm9yZzAeFw0wMzAzMzAxMjI5NDlaFw0zMzAzMjkxMjI5NDlaMHkxEDAO\n"\
        
"BgNVBAoTB1Jvb3QgQ0ExHjAcBgNVBAsTFWh0dHA6Ly93d3cuY2FjZXJ0Lm9yZzEi\n"\
        
"MCAGA1UEAxMZQ0EgQ2VydCBTaWduaW5nIEF1dGhvcml0eTEhMB8GCSqGSIb3DQEJ\n"\
        
"ARYSc3VwcG9ydEBjYWNlcnQub3JnMIICIjANBgkqhkiG9w0BAQEFAAOCAg8AMIIC\n"\
        
"CgKCAgEAziLA4kZ97DYoB1CW8qAzQIxL8TtmPzHlawI229Z89vGIj053NgVBlfkJ\n"\
        
"8BLPRoZzYLdufujAWGSuzbCtRRcMY/pnCujW0r8+55jE8Ez64AO7NV1sId6eINm6\n"\
        
"zWYyN3L69wj1x81YyY7nDl7qPv4coRQKFWyGhFtkZip6qUtTefWIonvuLwphK42y\n"\
        
"fk1WpRPs6tqSnqxEQR5YYGUFZvjARL3LlPdCfgv3ZWiYUQXw8wWRBB0bF4LsyFe7\n"\
        
"w2t6iPGwcswlWyCR7BYCEo8y6RcYSNDHBS4CMEK4JZwFaz+qOqfrU0j36NK2B5jc\n"\
        
"G8Y0f3/JHIJ6BVgrCFvzOKKrF11myZjXnhCLotLddJr3cQxyYN/Nb5gznZY0dj4k\n"\
        
"epKwDpUeb+agRThHqtdB7Uq3EvbXG4OKDy7YCbZZ16oE/9KTfWgu3YtLq1i6L43q\n"\
        
"laegw1SJpfvbi1EinbLDvhG+LJGGi5Z4rSDTii8aP8bQUWWHIbEZAWV/RRyH9XzQ\n"\
        
"QUxPKZgh/TMfdQwEUfoZd9vUFBzugcMd9Zi3aQaRIt0AUMyBMawSB3s42mhb5ivU\n"\
        
"fslfrejrckzzAeVLIL+aplfKkQABi6F1ITe1Yw1nPkZPcCBnzsXWWdsC4PDSy826\n"\
        
"YreQQejdIOQpvGQpQsgi3Hia/0PsmBsJUUtaWsJx8cTLc6nloQsCAwEAAaOCAc4w\n"\
        
"ggHKMB0GA1UdDgQWBBQWtTIb1Mfz4OaO873SsDrusjkY0TCBowYDVR0jBIGbMIGY\n"\
        
"gBQWtTIb1Mfz4OaO873SsDrusjkY0aF9pHsweTEQMA4GA1UEChMHUm9vdCBDQTEe\n"\
        
"MBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0\n"\
        
"IFNpZ25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2Vy\n"\
        
"dC5vcmeCAQAwDwYDVR0TAQH/BAUwAwEB/zAyBgNVHR8EKzApMCegJaAjhiFodHRw\n"\
        
"czovL3d3dy5jYWNlcnQub3JnL3Jldm9rZS5jcmwwMAYJYIZIAYb4QgEEBCMWIWh0\n"\
        
"dHBzOi8vd3d3LmNhY2VydC5vcmcvcmV2b2tlLmNybDA0BglghkgBhvhCAQgEJxYl\n"\
        
"aHR0cDovL3d3dy5jYWNlcnQub3JnL2luZGV4LnBocD9pZD0xMDBWBglghkgBhvhC\n"\
        
"AQ0ESRZHVG8gZ2V0IHlvdXIgb3duIGNlcnRpZmljYXRlIGZvciBGUkVFIGhlYWQg\n"\
        
"b3ZlciB0byBodHRwOi8vd3d3LmNhY2VydC5vcmcwDQYJKoZIhvcNAQEEBQADggIB\n"\
        
"ACjH7pyCArpcgBLKNQodgW+JapnM8mgPf6fhjViVPr3yBsOQWqy1YPaZQwGjiHCc\n"\
        
"nWKdpIevZ1gNMDY75q1I08t0AoZxPuIrA2jxNGJARjtT6ij0rPtmlVOKTV39O9lg\n"\
        
"18p5aTuxZZKmxoGCXJzN600BiqXfEVWqFcofN8CCmHBh22p8lqOOLlQ+TyGpkO/c\n"\
        
"gr/c6EWtTZBzCDyUZbAEmXZ/4rzCahWqlwQ3JNgelE5tDlG+1sSPypZt90Pf6DBl\n"\
        
"Jzt7u0NDY8RD97LsaMzhGY4i+5jhe1o+ATc7iwiwovOVThrLm82asduycPAtStvY\n"\
        
"sONvRUgzEv/+PDIqVPfE94rwiCPCR/5kenHA0R6mY7AHfqQv0wGP3J8rtsYIqQ+T\n"\
        
"SCX8Ev2fQtzzxD72V7DX3WnRBnc0CkvSyqD/HMaMyRa+xMwyN2hzXwj7UfdJUzYF\n"\
        
"CpUCTPJ5GhD22Dp1nPMd8aINcGeGG7MW9S/lpOt5hvk9C8JzC6WZrG/8Z7jlLwum\n"\
        
"GCSNe9FINSkYQKyTYOGWhlC0elnYjyELn8+CkcY7v2vcB5G5l1YjqrZslMZIBjzk\n"\
        
"zk6q5PYvCdxTby78dOs6Y5nCpqyJvKeyRKANihDjbPIky/qbn3BHLt4Ui9SyIAmW\n"\
        "omTxJBzcoTWcFbLUvFUufQb1nA5V9FrWk9p2rSVzTMVD\n"\
        "-----END CERTIFICATE-----\n";
       
    /* get a BIO */
        bio=BIO_new_mem_buf(mypem, -1);
   
    /* use it to read the PEM formatted certificate from memory into an X509
     * structure that SSL can use
     */
        PEM_read_bio_X509(bio, &cert, 0, NULL);
        if (cert == NULL) printf("PEM_read_bio_X509 failed...\n");
   
    /* get a pointer to the X509 certificate store (which may be empty!)
     */
    store=SSL_CTX_get_cert_store((SSL_CTX *)sslctx);
   
    /* add our certificate to this store
     */
    if (X509_STORE_add_cert(store, cert)==0) printf("error adding
certificate\n");
    /* all set to go */
    return CURLE_OK ;
}

int main(void)
{
    CURL * ch;
    CURLcode rv;

    rv=curl_global_init(CURL_GLOBAL_ALL);
    ch=curl_easy_init();
    rv=curl_easy_setopt(ch,CURLOPT_VERBOSE, 0);
    rv=curl_easy_setopt(ch,CURLOPT_HEADER, 0);
    rv=curl_easy_setopt(ch,CURLOPT_NOPROGRESS, 1);
    rv=curl_easy_setopt(ch,CURLOPT_NOSIGNAL, 1);
    rv=curl_easy_setopt(ch,CURLOPT_WRITEFUNCTION, *writefunction);
    rv=curl_easy_setopt(ch,CURLOPT_WRITEDATA, stdout);
    rv=curl_easy_setopt(ch,CURLOPT_HEADERFUNCTION, *writefunction);
    rv=curl_easy_setopt(ch,CURLOPT_WRITEHEADER, stderr);
    rv=curl_easy_setopt(ch,CURLOPT_SSLCERTTYPE,"PEM");
    rv=curl_easy_setopt(ch,CURLOPT_SSL_VERIFYPEER,1);
    rv=curl_easy_setopt(ch, CURLOPT_URL, "https://www.cacert.org/");

    /* first try: retrieve page without cacerts' certificate -> will fail
     */
    rv=curl_easy_perform(ch);
    if (rv==CURLE_OK) printf("*** transfer succeeded ***\n");
    else printf("*** transfer failed ***\n");
  
    /* second try: retrieve page using cacerts' certificate -> will succeed
     * load the certificate by installing a function doing the nescessary
     * "modifications" to the SSL CONTEXT just before link init
     */
    rv=curl_easy_setopt(ch,CURLOPT_SSL_CTX_FUNCTION, *sslctx_function);
    rv=curl_easy_perform(ch);
    if (rv==CURLE_OK) printf("*** transfer succeeded ***\n");
    else printf("*** transfer failed ***\n");

    curl_easy_cleanup(ch);
    curl_global_cleanup();
}
Received on 2005-08-24